Laminated Foil Substrate For Flexible Magnetic Recording Media
Original Publication Date: 1979-May-01
Included in the Prior Art Database: 2005-Feb-20
Biaxially oriented polyethylene terephthalate (PET) films presently used for flexible recording media are subject to numerous dimensional instabilities, such as thermal and hygroscopic expansion or contraction, and dimensional changes due to stress relaxation over long periods of time. Flexible films that are more dimensionally stable than PET film can be produced by laminating thin plies of a tough polymer film to both sides of a thin metal foil which is more dimensionally stable than PET film. The metal foil is not subject to hygroscopic expansion and, if the metal used has a low thermal expansion coefficient, the composite film is more dimensionally stable than PET film with respect to temperature change.